1. Field of the Invention
The present invention relates to a tube suitable for use in an anesthetic system as well as a tubing system and an anesthetic system.
2. Description of the Prior Art
Anesthetic systems described in, inter alia, U.S. Pat. Nos. 5,471,979 and 6,152,133 employ a unit for adsorption and desorption of gaseous anesthetic, arranged in a tubing system coupled to an anesthetic apparatus. This results in a large saving in the amount of anesthetic that is required for each patient.
However, the unit occupies a certain volume that with every breath fills with exhaled gas. This exhaled gas also includes carbon dioxide that with every inspiration also is returned to the patient.
Moreover, the choice of material used in the unit (for adsorption and desorption) can influence the amount of carbon dioxide that is returned since certain materials adsorb and desorb carbon dioxide apart from anesthetic.
Therefore, it is known to provide anesthetic systems of this type with an absorber unit for carbon dioxide in the inspiration branch of the tubing system (downstream of the unit for adsorption and desorption of gaseous anesthetic).
Even though this absorber unit does not need to retain the same volume of adsorbent as an absorber in a conventional anesthetic circle system (where all exhaled carbon dioxide is to be absorbed), it still has a volume that influences the system.
One problem with such an absorber unit is that it must still occupy a certain volume in order for the absorbent to be able to absorb all of the carbon dioxide. If this does not occur, measurement spikes may arise in a capnogram during inspiration. (Conversely, the volume is normally not of such a size that the patient is notably influenced).
A further problem with such an extra volume in the inspiration branch is that a rapid regulation of the anesthetic concentration may be complicated.